Crohn's disease (CD) affects up to 700,000 people in the United States. CD primarily affects younger adult patients. CD is difficult to diagnose because CD often presents nonspecific symptoms that may be associated with numerous, different, pathologies. A large proportion of CD cases involve the small bowel, and may involve the full thickness of the bowel wall. Additionally, the structural complexity of the small bowel can make interpretation of symptoms difficult. Thus, conventional approaches such as biopsies are not optimal for predicting patient response to treatment since biopsies may only assess superficial tissues and not the full thickness of the bowel wall, and may not be able to access the small bowel.
CD management involves early prediction of patient response to immunosuppressive (IS) therapy. Therapy decisions for patients suffering from CD or CD related symptoms are often based on patient symptoms, and are therefore subjective. Thus, therapy decisions for many patients result in poor outcomes. For example, up to 40% of patients may not respond to initial IS therapy, and may instead suffer from increasingly severe small bowel inflammation. Further complicating the diagnosis and treatment of CD is the lack of effective biomarkers to predict patient outcomes.
Magnetic resonance enterography (MRE) is a safe, noninvasive means of imaging CD presence and activity in vivo. MRE does not use harmful radiation, and, since it is non-ionizing, can therefore be used to obtain imagery of younger patients or patients who may need to undergo a large number of future imaging procedures. However, the application of MRE to early prediction of patient response to IS therapy is limited by poor inter-rater agreement and is also consequently subjective. Furthermore, the effective application of MRE to early prediction of patient response to IS therapy is limited by the lack of a definitive disease scoring system for CD.
CD response to IS therapy is conventionally assessed using the Crohn's Disease Endoscopic Index of Severity (CDEIS). CDEIS is, however, indicative of severity and not treatment outcome, and is thus not optimal when used to predict patient response to IS therapy. Another tool for assessing CD in a patient is the Magnetic Resonance Index of Activity (MaRIA). MaRIA indicates the severity of CD, and may be correlated with CDEIS. However, MaRIA is based on an expert evaluation, and is thus largely subjective. Furthermore, a patient's treatment response or outcome may not correlate with the severity of CD determined by CDEIS or MaRIA. Thus, predictive scores based on CDEIS or MaRIA are highly variable.
Since radiologists may be challenged to reliably predict patients' response to IS therapy using conventional approaches in clinically relevant time frames, ineffective therapies and procedures may be performed that ultimately result in no improvements for the patient. Patients who are provided with ineffective therapies may be subjected to treatment escalation that could otherwise be avoided. Treatment escalation, including hospitalization, medication escalation, or invasive procedures such as surgery or stricturoplasty, takes time, costs money, wastes resources that could be more beneficially employed, and puts a patient at additional risk. Therefore, CD patients would benefit from an accurate, non-invasive predictor of IS therapy response that facilitated more accurate and effective treatment of CD.